Thread-controlling mechanism.



L. u. ALLEN a B. F. CROSBY. THREAD CONTHOLLING MECHMHSM. A APPLICATWN F|LED1UNE30| |916. 1 275 999. Patented Aug.,2o, 191s s snfirs-snn l.

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` WITNESS E. B. ALLEN 6L B. F. CROSB'Y. THREAD CUNTROLLING MECHAISM.

APPLlcAloN FILED :un: au. |915.

1,275,999. Patented Aug. 2o, 1918.

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A TTOH/VEY E. B. ALLEN 6L B. F. CROSBY.

THREAD CONTROLLING MECHANISM.

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1 ,27 5 ,999 Patentd Aug. 20, 1918.

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UNITED STATES PATENT OFFICE.

EDWARD B. ALLEN AND BENJAMIN F. CROSBY, OF BRIDGEPORT, CONNECTICUT, ASSIGN- ORS T0 THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

THREAD-CONTROLLING MECHANISM'..

Specification of Letters Patent.

Patented Aug. 20, 1918.

Application led .Tune 30, 1916. Serial No. 106.761.

To all who/n it may concern:

Be it known that we, EDWARD B. ALLEN and BENJAMIN F. CROSBY, respectively a citizen of the United States and a subject of the King of Great Britain, both residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Thread- Umitrolling Mechanisms, of which the following is a specification, reference being had (herein lo the accompanying drawings.

This invention relates to overseaming stitch-forming mechanism in which means are provided for coperation with a reciprocating needle for concatenation of threadloops above and below the work; and it has for its object to insure the initial concatenation of such thread-loops below the work in beginning the stitching period. If the initial concatenation of thread-loops at the beginning of a seam were effected above the fabric, an. objectionable loose thread would be left upon its face and the firststitch of a series would be loosely made. It is accordingly the object of the present invention to so begin a seam that the end of such thread will be invariably attached initially below the fabric.

While the present improvement is not limited to employment in connection with any particular variety of stitch-forming mechanism of the t pe described, it is designed particularly or application to mechanism comprising a reciprocating threadcarrying needle and cooperating lowerthread loop-taking means includin a looper adapted to seize and spread nee le-thread loops below the work and an overedge thread-carrying loop-presenting needle or element adapted to carry its thread through the needle-thread loop so spread and present a loop of its own thread above the work for passage of the needle in its succeeding thrust. To insure the proper presentation of the lower-thread loop, the overedge needle in the initial portion of its descending or retractive movement has a dwell involving a slight reversal of such initial movement so as to allow ample tiinefor passage of the upper needle through the loop of lower thread thus formed.

The present invention consists in means ing means for maintaining the lower thread taut when its respective loop-presenting clement is in loop-presenting position in thc initial stitch-forming cycle of a series and for insuring the proper formation of lowerthread loops at the corresponding stages of the. succeeding cycles of the series.

In its preferred embodiment, the invention is applied to a buttonhole machine constructed in substantial accordance with that of the United States patent to Edward B. Allen, No. 1,162,207, dated November 30, 1915, and comprises a thread-drawing or slackthread controlling lever adapted for engagement with the lower thread at a point between the usual fixed thread-end clamp upon the traveling work-holder and an intermittently acting thread-nipper with actuating means whereby it is closed upon the lower thread while the upper needle is passing through the lower-thread loop above the work. The rotary looper-actuating shaft. preferably carries a controlling cam 'acting upon the thread-drawing lever`` constituting a loop-robbing device which is normally maintained in retracted and inactive positionby a latch or detent adapted to be released, in the machine referred to, by engagement of a tappet-arm carried by the traveling cutting device in a buttonhole cutting operation preceding each stitching operation.

In the accompanying drawings, Figure 1 is a rear side elevation of a portion of the said buttonhole machine provided with the present improvement, and Fig. 2 a front end View of the same with the detachable forward port-ion of the base omitted. Fig. 3 is a. perspective view of the parts represented in the preceding figures, portions of which are represented in dotted lines. Fig. 4 is an elevation of a portion of the lower-thread loop-presenting, needle and its actuating means. Fig. 5 is a perspective view of the thread-nipping device and its carrier-plate and Fig. 6 a transverse section of the same upon a larger scale. Fig. 7 is a perspective view of the thread-drawing lever and its latch, and Figs. 8, 9, 10 and 11 are perspective views representing parts of the actuating means for the loop-taking devices. Fig. 12 is a perspective View representing the upper needle and the cooperating looppresenting element under the action of the looprobbing device.

The machine is represented with the usual hollow rectangular base l from the rear end of which rises the hollow standard 2 of the bracket-arm. Journaled within and longitudinally of the base is the 1nainshaft 3 carrying at its rearward end the loose belt-wheel 4 adapted for detachable connection with the main-shaft by means of a stop-motion comprising the clutch-ring 5 adapted for engagement by the spring-pressed tooth 6 of the swinging stop-lever 7 mounted upon the rockshaft 8 which is journaled in the bracket 9 sustained by the base 1. The stopmotion acts as usual to control the period of operation of the main-shaft 3, and hence of the stitch-forming niechanisn'i which comprises the reci1n'ocating eye-pointed upper needle n, the loop-seizing element or looper Z and the eye-pointed lower-thread-loop presenting needle or element t.

As represented in the accompanying drawings, the looper mechanism is substantially the same as that of the said Patent No. 1,162,207. The main-shaft 3 has secured upon its forward end, as represented in dotted lines in Fig. 1, the gear-wheel 10 meshing with the toothed pinion 11 upon the rearward end of the looper-actuating shaft 12 journaled in bearings sustained by the cross-member 13 of the base 1 and carrying upon its forward end the crank 14. The crank 14 is connected by means of the link 15 with a stud-pin 16 carried by the swinging lever 17 having its hub 18 fulcrumed upon the stud-screw 19 which is sustained upon the frame member 13.

The lever 17 is connected at its free end by means of the link 20 with the stud-screw 21 carried by the plunger-rod 22 suitably journalcd in the frame and provided with a lateral arm 23 forked at its outer end to enter the annular notch or neck 24 formed in the lower end of the tubular plungerrod 25.

The rod 25 is slidingly journaled within a bearing boss 26 depending from the rotary turret 27 which is journaled within a suitable bearing of thecurb 28 sustained by the frame member 13, and is provided with a laterally extending head 29 apertured at its outer end to it the guide-post 30 adjacent which it is connected by means of the link 31 with the swinging lower-needle carrier-arm 32 fulcrumed at 33 upon the supporting post 34 mounted upon the carrier 27. The head 29 of the rod 25 is apertured to fit the spiral gear 35 operatively connected with the rocking and bodily-reciproeating carrier 36 for the looper Z. The upper and lower needles operate as usual through a needle-throat 37 sustained by a bracket 38 carried by the turret 27.

In the mechanism as thus described, the swinging lever 17 and link 20 constitute a toggle connection between the looper-ac;- tuating shaft and the looping elements cooperating with the needle. The movement of the toggle beyond straightened position, as represented in Fig. 2, causes a dip or reaction of the lower-needle or loop-presenting element t in the upper portion of its stroke to form and sustain a lower-thread loop in position for the upper needle ln to pass through it, the lower-thread loop having entered a loop of upper thread seizedfrom the needle by the looper Z and distended for passage of the lower needle t.

Suitably sustained by the cross-member 13 is a bracket-plate 39 having secured thereto the block 40 formed with a vertical socket 41 in which is journaled the shouldered plunger-rod 42 whose reduced and threaded upper portion projects above said bearing block and carries the adjustable threadnipping disk 43. The upper end of the block 40 affords the fixed element of a. nipping device of which the movable element is the disk 43, which is normally pressed upon the fixed element by means of a spring 44 embracing the reduced portion of the rod 42 between the shoulder of which and the opposite end of the socket 41 it is interposed. The rod 42 carries a lateral stud 45 passing through a slot 46 in the bearing block 40 by which the endwise movements of the rod 42 are limited.

The rod 42 has secured in its lower end the contact-screw 47 which is ladjust-ably secured in position by means of" a lock-nut 48. adapted for en agement by one arm of a rock-lever 49 ulerumed intermediate its ends upon the stud-screw 50 tapped into an extension of the member 13 and'having its opposite end resting against a cam-element 18 afforded by the flattened lower side of the hub 18 of the swinging lever 17 by the operative movements `of which the rocklever 49 isoperated to lift the plungerrod 42 in each stitch-forming cycle to permit the measuring off of a supply of lower thread for the succeeding stitch, the thread-nipper remaining' closed at other times under the action of the spring 44.

Secured 'to the bracket-plate 39 by means of the shouldered tension stud 51 is the plate 52 carrying the lateral thread guide-pin 53 adjacent which is the clearance slot 54 extending from its lower edge. The plate 52 is provided at its outer end with a lateral lip 55 at the base of which is the thread slot 56 having at its upper end the threading slit 57. To the tension stud 51 are ap- The head of the Contact screw 47 isv plied the tension-disks 58 pressed together and upon the plate 52 by means of the sprin 59 interposed between the outer ten sionisk and the nut 60 applied to the outer threaded portion of the stud 51. In threading the machine, the lower thread s is passed through an aperture 61 in the side of the base 1 ('Fig. 3) through the eye in the guideplate 61 secured to the block 40 and between the nipping elements 40 and 43 and the tension disks 58, thence over the guide-pin 53 and through the threadslot 56 from which it is led upwardly through the tubular rod 25 to the lower needle or loop-presenting element t and thence beneath the usual threadclamping spring-plate 62 secured by means of the screw 62 upon one of the work-holding clamp-plates 63.

Rigidly secured to the lateral arm 23 of the rod 22 is the pull-off arm 64 provided at its outer end with an outwardly extending finger 64 normally disposed below the thread aperture of the plate 61', but adapted to be moved upwardly, as represented in Figs. 2 and 3, to draw thread from the lower'thread supply while the nipping ele ments are closed upon the thread.

Mounted upon a shouldered stud 65 sustained by the member 13 is an angle-lever having a lateral arm 66 and an upwardly extending arm 67, the latter being formed with an angular pawl-shaped extremity. To the lateral arm of this lever is adjustably secured by means of the screw 68 an angular thread-engaging arm 69 having an inwardly extending finger 69 movable, when the arm 66 rises, into the clearance slot 54. The lever-arm 66 is normally pressed downwardly by means of the spring 70 coiled around the hub 66 of the anglelever and connected at its opposite ends respectively with said lever and the framemember 13.

The thread-engaging arm 69 is normally maintained in upper inoperative position with the finger 69 within the slot 54 above the thread s by means of a pawl or detentarm 71 fulcrumed upon a fixed stud-screw 72 and having near its outer end a notch affording a shoulder 73 which is inclined downwardly and backwardly and therefore at an angle with the direction of movement of the detent-arm. When the pawl is disengaged from the upper extremity of the lever-arm 67, the rounded free end of the arm 66 is maintained, under the action of the spring 70, in contact with the controlling cam 74 carried upon the outer face of the crank 14.

As represented in Fig. 2, the cam 7 4 has a nearly semi-circular portion concentric with the loo er-actuatin shaft 12 and an opposite attened portion disposed nearly dia metrically of said shaft. The point of the arm 67 normally rests at the base of the shoulder 73, in which position the arm 66 is maintained slightly retracted from Contact with the concentric portion of the cam 74.

The lifting of the detent 71 while the initial end of the eccentric portion of the cam is presented to the lever-arm 66 permits the latter to contact with the same and to descend in its continued contact with the eccentric portion of the cam as the shaft 12 performs its initial rotation, thereby causing the thread-finger 69 to descend, as represented in Figs. 2 and 3, to draw thread between the nipper and the loop-presenting element t. As the outer portion of the arm 66 resumes engagement with the circular portion of the cam, the angle-lever is rocked to lift the thread-finger 69 above the guide` finger' 53 and the point of the arm 67 engages the lower portion of the inclined shoulder 73 by which it is forced backwardly slightly in the descent of the detent-arm 71 under the action of its spring 75 which is coiled around the stud 72 and has its extremities connected respectively with the arm 71 and a fixed part of the machine frame. By this means the arm 66 is returned to retracted position slightly above the concentric portion of the cam 74.

Journaled in bearings 76 above the basel and extending crosswise of the standard 2 is the cutter-actuating shaft 77 having loosely mounted thereon the grooved driving pulley 78 adapted to be set in driving relation with said shaft for production of a single rotation thereof at a time by means set forth in the United States patent to E. B. Allen No. 1,048,786, of December 31, 1912. Fixed upon the cross-shaft 77 are the cutter-actuating cams, including the cam-disk 79 which is formed with the cam-groove 80 entered by a stud 81 upon the link-bar 82 which is slotted in one end portion to embrace a guide-block fitted upon the shaft. At its apposite end, the bar 82 is adjustably connected by means of the bolt 83 with an extension of one of the standing lugs 84 of the fulcrumesustaining slide-plate 85 slidingly mounted upon the bed of the machine and carrying the fulcrum-pin 86 (Fig. 3) for the upper and lower cutter-levers 87 and 88 which are provided respectively with the buttonhole cutter 89 and the cutter-plate or anvil 90.

The slide-plate 85 is shown formed with a depending lug 91 carrying a block 92 to which is secured by screws 93 the down-` wardly extending arm 94 terminating in a forwardly projecting tappet-finger 95 whose outer portion normally extends beneath the out-er end of the lath-arm 71.

The upper or operative edge of the finger 95 is slightly' inclined forwardly and downwardly, so that in its movement with the fulcrum-plate in carrying the cutting members from normal retracted position into operative or cutting position, the latch-arm 71 is lifted. This permits the point of the lever-arm (56 to move laterally under the action of its spring slightly beyond the detent-shoulder 73, as represented in Fig. 3, to maintain the detent-arm 71 out of latching relation with the lever-arm 67.

The cam 74 at this time presents to the lever-arm 66 the initial end of the eccentric portion of the cam 74 just beyond the termination of the concentric portion, and in the initial rotation of the controlling cam, the thread-drawing finger 69 descends to its lowest position so as to insure maintenance of the lower thread taut at the stage of the stitch-forming cycle wherein the point of the upper needle passes the blade of the lower needle or loop-presenting element. The finger 69 thereafter quickly rises to upper retracted position wherein it is held by engagement of the detent-arm 71 with the lever-arm 67.

Preparatory to a buttonhole producing operation, the cutter-levers 87 and 88 are retracted from operative position and the cutting elements 89 and 90 are separated.

The toggle device 17, 20, being bent to extreme position, the lower needle is in its lower position while the upper needle is above the work-holder for insertion of the work.

Upon starting the machine, the cutting device advances for cutting a buttonhole slit and the tappet-arm 94 at the same time lifts the detent-arm 71 for release of the threaddrawing element 66. Upon the retraction of the cutting device and the starting of the stitch-forming mechanism, the lower needle rises through the buttonhole slit and performs its initial retractive movement followed by a dwell in loop-presenting position,

at which time the action of the thread-drawing lever-arm 66 causes the lower thread leading from the eye of the lower needle through the buttonhole slit to remain taut, thereby causing the point of the upper needle to pass at the outer side of the lower thread thus ositioned, as represented in Fig. 12. Durmg the rise of the upper needle the thread-nipper 40, 43, is closed upon the lower thread, the pull-oil' element 64 rises to draw oli' a new supply of lower thread and the thread-drawing element 66 begins its descent to draw up the thread extending from the nipper through the needle to the thread-clamp 62.

As the upper needle begins its rise from extreme lower position, a thread-loop is seized therefrom by the looper l and spread for passage of the lower needle in its sncceeding rising movement to present a loop of its thread for passage of the upper needle, the thread-drawin element 66 being meanwhile returned un er the action of the cam -74 and the detent shoulder73 to extreme upper position in which it is maintained for the remainder of the buttonhole produc-ing ol'xsration. An initial upper-thread loop having thus been seized below the work and locked by subsequent passage of the succeeding lower-thread loop, the stitching now proceeds in the ordinary manner to the end of the stitching period. Thus the first concatenation of a lower-thread loop with the upper thread occurs below the fabric from which the loose end of lower thread consequently extends, with the result that the first stitch upon the upper face of the fabric is iirmly set and is not left in unfinished condition.

While the present improvement is herein shown and;described as embodied in a but-V threads wherein means are provided orcooperation with the needle both above and below the work, and that the means which may be employed for setting the loop-robbing device in operation will be dependent upon the nature of the machine to which the device is applied.

Having thus set fort-h the nature of the invention, whatwe claim herein is 1. In a sewing machine, the combination with overseaming stitch-forming mechanism including a reciprocating needle and a loop-presenting element cooperating therewith for concatenation of thread-loops at opposite sides of the work, of means for preventing seizure of a thread-loop by the needle during its initial thrust at the beginning of a stitching operation, whereby to secure the initial concatenation ofthreadloops at the underside of the work'.

2. In a sewing machine, the combination with overseaming stitch-forming mechanism including a reciprocating upper-threadearrying needle and a lower-thread-carrying element coperating therewith fory concatenation .of thread-loops alternately at opposite sides of the work, of a lower-threadengaging device for preventing seizure of a lower-thread-loop by the needle during its initial thrust at the beginning of a stitching operation, whereby to secure the initial concatenation of thread-loops at the lower side of the Work.

3. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating looppresenting element, means acting, during an initial thrust only of said needle for seizure of a thread-loop from said loop-presenting element, to prevent the seizure of said loop, but ineffective to perform such function in a succession of needle-thrusts thereafter.

4. In a sewing machine, in combination,

stitch-forming mechanism comprising a reciprocating needle and a cooperating threadcarrying loop-presenting element, means acting, during an initial thrust only of said needle for seizure of a thread-loop from said loop-presenting element, to prevent the seizure of said loop, but ineffective to perform such function in a succession of needlethrusts thereafter.

5. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating threadcarrying loop-presenting element, a threaddrawing element acting upon the thread carried by said loop-presenting element, and means for insuring a single actuation only of said thread-drawing element for maintaining said thread taut during a loop-seizing thrust of said needle at the beginning of a series of stitches.

6. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating threadcarrying loop-presenting element, a threaddrawing element acting upon the thread carried by said loop-presenting element, actuating means for said thread-drawing element, and controlling means for insuring the action of said actuating means in an initial stitch-forming cycle of a series and for preventing its operation immediately before and after said initial stitch-forming cycle.

7. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating looppresenting element, spaced thread-clamping means acting' upon a section of the thread of said loop-presenting element at opposite sides of the latter, and means whereby said section of thread is maintained taut in the loop-presenting stage of an initial stitchforming cycle of a series but is allowed to become slackened for seizure of the threadloop in the next succeeding cycle.

8. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating looppresenting element, spaced thread-clamping means acting uponvthe thread of said loopresenting element at opposite sides of the atter, and loop-preventing thread-drawing means acting upon said thread between one of said thread-clamping means and the looppresenting element during the needle-thrust of an initial stitch-forming cycle of a series and inactive thereon during the needlethrust neXt succeeding the same.

9. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating looppresenting element With means for imparting thereto reciprocating movements with adwell while in loop-presenting position, means acting upon the thread carried by said element during the dwell of the latter the needle and while the nipper is closed upon the thread.

11. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating looppresenting element, of a thread-drawing element adapted to act upon the thread carried by said loop-presenting` element, and controlling means for insuring the action of said thread-drawing element upon the thread while said loop-presenting element is in loop-presenting relation with the needle in an initial stitch-forming cycle and its inaction upon the thread in the corresponding stages of a succession of stitch-forming cycles next succeeding said initial stitchforming cycle.

12. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating loop-presenting element, of a normally inactive thread-drawing element adapted to act upon the thread carried by said looppresenting element, and controlling means for insuring the action of said thread-drawing element upon the thread while said loop-presenting element is in loop-presenting relation with the needle in an initial stitch-forming cycle and its inaction upon the thread in the corresponding stages of a succession of stitch-forming cycles next succeeding said initial stitch-forming cycle.

13. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocatin needle and a cooperating loop-presenting element, of a spring-actuated thread-drawing element adapted to act upon the thread carried by said loop-presenting element, a detent for maintaining said thread-,drawing element normally inactive, means acting preparatory to a stitching period for tripping said detent to release said thread-drawing element, and controlling means acting within an initial stitch-forming cycle to permit an operative movement of the thread-drawing element and to thereafter restore to it normal relation with said detent before the completion of the next succeeding stitch-forming cycle.

14. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a coperating loop-presenting element, of a spring-actuated thread-drawing element adapted When released to draw upon the thread carried by said loop-presenting element, controlling means operative during a stitching period for causing reciprocal tl'iread-dravving and retractivc movements of said thread-drawing element, a detent comprising lneans for normally retracting and holding said thread-drawing element out of contact relation With said controlling means, and tripping means for said detent.

15. In a sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a coperating loop-presenting element, a spring-actuated thread-drawing element adapted to act upon the thread carried by said loop-presenting element, controllin means operative during a stitching period for causing reciprocal thread-drawing and retractive movements of said thread-drawing element, a reciprocatory detent provided With a detaining shoulder inclined to its direction of movement and adapted for engagement With a part of said thread-drawing element, and tripping means for said detent.

16. In a buttonhole sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a cooperating loop-presenting element, and buttonhole cutting mechanism, means acting, during an initial thrust only of said needle for seizing a thread-loop from said loop-presenting element, to prevent the seizure of said loop, but ineifective to perform such function in a succession of needle thrusts thereafter, and means operatively connected with said cutting mechanism for setting the irst-named means in action.

17. In a buttonhole sewing machine, in combination, stitch forming mechanism comprising a reciprocating needle and a cooperating loop-presenting element, and buttonhole cutting mechanism, a normally inactive thread-drawing element, means operative Within a stitching period for actuating the same, and means under the con` trol of the cutting mechanism for setting the same in action.

18. In a buttonhole sewing machine, in combination, stitch-forming mechanism comprising a reciprocating needle and a oooperatmg loop-presenting element, a springactuated thread-drawing element adapted to act upon the thread carried by said looppresenting element, a detent for maintaining said threaddrawing element normallyy inactive, tripping means for said detent with means for actuating the same intermediate stitch-forming periods, and means controlling means for insuring the operation of said thread-drawing element in one stitch-forming cycle and its return to normal relation'vvith the detent in a succeeding stitch-forming cycle.

20. In a buttonhole sewing machine, in combination, stitch-forming mechanismcomprising a reciprocating needle and a cooperating loop-presenting element, and a traveling buttonhole cutting device movable toward and from the stitch-forming mechanism, a spring-actuated thread-drawing element adapted to act upon the thread carried by said loop-presenting element, controlling means for insuring thread-drawing and retractive movements of said threaddrawing element Within a stitch-forming period, a detent for maintaining said threaddrawing element normally in retracted position, and tripping means for said detent carried by and partaking of the traveling movements of said cuttin device.

21. In a sewing machlne, the combination with a reciprocating needle a threadcarrying loop-presenting element and actuating means for said element including atoggle device, of a nipping device for the thread of said loop-presenting element, and operating means therefor lncluding means connected with and operated by said toggle device.

22. In a sewing machine, the combination With a thread-carrying loop-presenting element and actuating means therefor including a toggle device with a cam-element formed upon one of its component members, of a nipping device for the thread of said loop-presenting element, and a rock-lever operatively ,connected With said nipping device and deriving operative movements from said cam-element.

23. In a sewing machine, the combination with looper mechanism comprising a toggle device, of an intermittently acting threadnipping device, a thread-guide spaced therefrom, a pull-oli member movable intermediate said nipping device and thread-guide, and means including independent connections with said toggle device for imparting operative movements to said nipping device and pull-off member.

24C. In a sewing machine, the combination with looper mechanism comprising aftoggle device and a reciprocating rod actuated thereby, of an intermittently acting threadnipping device, a thread-guide spaced theref1on1,.and a pull-oft' member movable intermediate said nipping device and threadguide and deriving operative movements from said reciprocating rod.

25. In a sewing machine, the combination with looper mechanism including a toggle device with a cam-element formed upon one of its component members and a reciprocating rod deriving operative movements from said toggle device, of an intermittently acting thread-nipping device, an operative connection between the nipping device and said cam-element, a thread-guide spaced from said nipping device, and a pull-off member movable intermediate said nipping device and thread-guide and deriving operar tive movements from said reciprocating rod.

In testimony whereof, We have signed our names to this specification.

EDWARD B. ALLEN. BENJAMIN F. CROSBY.

Copies of this patent may be obtained for ve cents each, by addressing the "Gommissioner of Patents, Washington, D. c. 

